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Mohanty P.,Indian Institute of Technology Delhi | Pant K.K.,Indian Institute of Technology Delhi | Parikh J.,SVNIT | Sharma D.K.,Indian Institute of Technology Delhi
Fuel Processing Technology | Year: 2011

CuO-CoO-Cr2O3 mixed with MFI Zeolite (Si/Al = 35) prepared by co-precipitation was used for synthesis gas conversion to long chain hydrocarbon fuel. CuO-CoO-Cr2O3 catalyst was prepared by co-precipitation method using citric acid as complexant with physicochemical characterization by BET, TPR, TGA, XRD, H2-chemisorptions, SEM and TEM techniques. The conversion experiments were carried out in a fixed bed reactor, with different temperatures (225-325 °C), gas hourly space velocity (457 to 850 h-1) and pressure (28-38 atm). The key products of the reaction were analyzed by gas chromatography mass spectroscopy (GC-MS). Significantly high yields of liquid aromatic hydrocarbon products were obtained over this catalyst. Higher temperature and pressure favored the CO conversion and formation of these liquid (C5-C15) hydrocarbons. Higher selectivity of C5 + hydrocarbons observed at lower H 2/CO ratio and GHSV of the feed gas. On the other hand high yields of methane resulted, with a decrease in C5+ to C11+ fractions at lower GHSV. Addition of MFI Zeolite (Si/Al = 35) to catalyst CuO-CoO-Cr2O3 resulted a high conversion of CO-hydrogenation, which may be due to its large surface area and small particle size creating more active sites. The homogeneity of various components was also helpful to enhance the synergistic effect of Co promoters. © 2010 Elsevier B.V. All rights reserved.

Lal A.,SVNIT | Singh B.N.,Indian Institute of Technology Kharagpur
Journal of Thermoplastic Composite Materials | Year: 2010

This work deals with the stochastic free vibration of laminated composite plates subjected to a thermal loading with general boundary conditions by taking into account the randomness in lamina material properties and thermal expansion coefficients. The system equations have been derived based on higher order shear deformation theory incorporating rotary inertia effects. A C0 finite element method is used for treating the random eigenvalue problem. A mean centered first-order perturbation technique is adopted to examine the stochastic characteristics of thermal free vibration response. The results have been compared with those available in the literature and independent Monte Carlo simulation. © 2009 SAGE Publications.

Journal of Engineering Design | Year: 2010

This paper presents a methodology for the selection of a best product end-of-life (EOL) scenario using digraph and matrix methods. An 'EOL scenario selection index' is proposed to evaluate and rank the alternative product EOL scenarios. The index is obtained from an 'EOL scenario selection attributes func- tion'obtained from the 'EOL scenario selection attributes digraph'. The digraph is developed considering EOL scenario selection attributes and their relative importance for the considered product. An example is included to illustrate the approach. © 2010 Taylor & Francis.

Singh B.N.,Indian Institute of Technology Kharagpur | Lal A.,SVNIT
International Journal of Pressure Vessels and Piping | Year: 2010

This study deals with the stochastic post-buckling and nonlinear free vibration analysis of a laminated composite plate resting on a two parameters Pasternak foundation with Winkler cubic nonlinearity having uncertain system properties. The system properties are modeled as basic random variables. A C0 nonlinear finite element formulation of the random problem based on higher-order shear deformation theory in the von Karman sense is presented. A direct iterative method in conjunction with a stochastic nonlinear finite element method proposed earlier by the authors is extended to analyze the effect of uncertainty in system properties on the post-buckling and nonlinear free vibration of the composite plates having Winler type of geometric nonlinearity. Mean as well as standard deviation of the responses have been obtained for various combinations of geometric parameters, foundation parameters, stacking sequences and boundary conditions and compared with those available in the literature and Monte Carlo simulation. © 2010 Elsevier Ltd.

Jagtap K.R.,SVNIT | Lal A.,SVNIT | Singh B.N.,Indian Institute of Technology Kharagpur
Composite Structures | Year: 2011

This paper presents the stochastic nonlinear free vibration response of elastically supported functionally graded materials (FGMs) plate resting on two parameter Pasternak foundation havingWinkler cubic non-linearity with random system properties subjected to uniform and nonuniform temperature changes with temperature independent (TID) and dependent (TD) material properties. System properties such as material properties of each constituent's material, volume fraction index and foundation parameters are taken as independent random input variables. The basic formulation is based on higher order shear deformation theory (HSDT) with von-Karman nonlinear strains using modified C 0 continuity. A direct iterative based nonlinear finite element method in conjunction with first order perturbation technique (FOPT) developed by last two authors for the composite plate is extended for FGM plate to compute the second order statistics (mean and coefcient of variation) of the nonlinear fundamental frequency. The present outlined approach has been validated with those results available in the literature and inde-pendent Monte Carlo simulation (MCS). © 2011 Elsevier Ltd.

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